Fish roe: a "hidden" allergen in japanesse food?

BACKGROUNDSalmon roe (SR) is a component of traditional Japanesse Food. As Sushi has become widespread, so has SR consumption. Allergic reactions to roes from fish are not commonly reported in western countries and only a few cases can be found in the literature.

CASE REPTORTA 4-years-old girl was seen in consultation for an anaphylactic reaction after ingestion of 1 roe of salmon. She had a history of egg allergy with tolerance to cocked egg. Her parents were eating japanesse food and she tasted one SR. Within 15 minutes after ingestion she developed facial angioedema and hoarse voice with no wheezing. Her parents gave her a dose of oral antihistaminic and took her to hospital where she was given oral corticosteroids with resolution. Two years before, she presented facial urticaria and angioedema after ingestion of egg-containing soup and touching SR. Then, symptoms were wrongly attributed to egg allergy. The girl eated fish (salmon and white fish) and shellfish after the reaction with no symptoms

The skin prick testing were negative to commercial fish (tuna, codfish, hake and sole), shellfish (clam, shrimp and squid) and Anisakis. Prick to prick with salmon roe was positive (26 mm wheal flare). The results of prick by prick with cooked and smoked salmon were negative and the diameter of sturgeon (Russian beluga) and raw salmon wheals were less than histamine control (5 mm flare). Salmon specific- IgE was <0.1 KU/L and Serum sample was taken for roe specific IgE measurement and immunoblotting. We did not perform an oral challenge with roe in our patient given the severity of the initial reaction.

CLINICAL RELEVANCEOur patient developed a severe reaction to SR without concomitant fish allergy. Fish roe may be a cause of allergic reactions and clinicians should be aware of possible reactions to roe in patients who test negative for fish or shellfish allergy when there is a suspicion of seafood allergy.